Such gluing units are known, for example, for labeling machines for labeling bottles in the beverage industry. The glue roller is used to transfer glue onto so-called pallets, which in turn apply the glue onto the back side of the labels to be applied. Using a gripper cylinder, the labels are then removed from the pallets and applied to the respective containers.
In known gluing units, glue rollers are usually plugged onto a polygonal shaft. The shaft has a ball bearing mounting at the lower end in the housing. The upper end of the shaft has a counter-bearing in a hinged lid. For changing the glue roller, the lid is opened and the glue roller is then pulled off upwardly from the shaft.
The glue roller has an end-to-end hub with a polygonal profile. The shaft-hub connection should be designed with possibly no tolerance but well detachable. This is achieved for known glue rollers by the selection of respective materials. The shaft is typically made of stainless steel, while the hub is made of a copper and/or brass alloy. This results in a composite construction that is relatively complex. In addition, the internal centering requires heavy cast elements, so that the mass of known glue rollers is correspondingly large. This is also ergonomically unfavorable because the removal of known glue rollers is usually performed by raising, as described above.
Glue rollers, which can be removed laterally, are also known. This is ergonomically more favorable, since lifting the heavy glue roller can be largely avoided. However, for known systems, it is quite complex to separate the connection between the glue roller and the drive motor.